1. Field of the Invention
The present invention relates to a solenoid valve fixing structure for fixing a solenoid valve to an intake manifold.
2. Description of the Prior Art
A system for reserving hydro-carbon gas using an activated carbon canister is well known; in which a hydro-carbon gas evaporated from the fuel in a fuel tank, due to engine heat or external heat, is temporally reserved in an activated carbon containing canister, and while the vehicle is running, the reserved gas is sent into the intake manifold of the engine of a vehicle so as to be burned out, for protecting the emission of the hydro-carbon gas into the atmosphere.
An apparatus for suppressing evaporated fuel gas emission, which uses such a system for reserving hydro-carbon gas in an activated carbon containing canister, has usually a solenoid valve for opening and closing channels for the evaporated fuel gas and/or the air. A solenoid valve fixing structure in the prior art, which is arranged between a canister and an intake manifold, is explained below.
FIG. 25 is a schematic diagram of an apparatus for suppressing the evaporated fuel gas emission in the prior art. FIG. 26 is a plan view of a part of a fixing plate disposed at an intake manifold. FIG. 27 is a partially cross-sectional view of a solenoid valve fixing structure according to the prior art.
Reference numeral 21 denotes a fuel tank, the fuel tank is connected with a separator 23 through a channel 22. The evaporated gas from the fuel tank is separated into a liquid component and a gas component by the separator 23. Reference numeral 24 denotes a pressure sensor for diagnosis, which detects pressure change of the evaporated fuel gas, for detecting leakage of the evaporated fuel gas while the vehicle is running. Reference numeral 25 denotes an activated carbon containing canister for reserving the evaporated fuel gas temporally. The canister 25 has an air introducing hole 26, an evaporated fuel gas introducing hole 27 and an outlet hole 28 of the reserved fuel gas, which is lead to an intake manifold 29 of the engine.
The purge quantity of the evaporated fuel gas from the canister 25 to the intake manifold 29 is controlled by a solenoid valve 30. As shown in FIGS. 26 and 27, the solenoid valve 30 is fixed to a fixing plate 31, which projects from the intake manifold 29. A bolt 34 fixes the solenoids valve 30 to a fixing hole 32 disposed in the fixing plate 31. An insert bush 33 is disposed between the fixing plate 31 and the bolt 34.
An air cut valve 35 controls the opening and closing of a channel communicating with the air introducing hole 26 of the canister 25. Ordinarily, the air cut valve 35 keeps an opening state so that the air introducing hole 26 is open to the atmosphere. This air cut valve 35 is closed, only when the communication from the atmosphere shall be cut off, at diagnosis of the apparatus is made. The air cut valve 35 is connected to the air introducing hole 26 through a hose 36.
The mounting of the solenoid valve onto the intake manifold 29 is carried out as follows: An insert bush 33 is previously set into the fixing plate 31 of the intake manifold 29; A bolt 34 is inserted into the solenoid valve 30; The bolt 34 is screwed into the insert bush 33.
Due to such a structure, the solenoid valve fixing structure of the prior art has following drawbacks. First, a bolt 34 must be screwed into the insert bush 33. Therefore the fixing is not easy and it takes a long time. Second, the solenoid valve 30 cannot be fixed compactly, because the solenoid valve is fixed onto a fixing plate 31, jutting from the manifold 29.
Of course, the fixing using a bolt 34 can be made easy, by changing the design of the external form of a solenoid valve 30. However the change of a design entails to a high fabrication cost.
A box-formed solenoid valve installed on a manifold is disclosed in JP-A-6-185654, as another prior art. The solenoid valve described in it also requires a change of designing of its external form. Thus it entails to a high fabrication cost, too.